Patent Literature 1 discloses an input device including a character input interface unit that performs switching among a plurality of characters assigned to a same key, according to the number of times at which the key has been depressed. This input device has a function of judging that the determination operation of one of the assigned characters being currently displayed has been performed when no key input is made for a given period of time and then causing a cursor to move to an adjacent position. By utilizing this function, a key operation for moving the cursor, which also serves as the determination operation of the character, can be omitted during input of the character.
Patent Literature 2 discloses an information input device that automatically selects a function of executing a subsequent operation, in response to a result of measurement of a speed at which information to be input has been input. Specifically, as shown in FIG. 6 of Patent Literature 2, according to the speed at which a character has been input, subsequent display of content such as the meaning of the input character or selection of a dictionary for use is proposed.